Documents show transport officials wanted to remove dodgy handbrakes from more than 1000 trucks by the middle of last year but it still hasn't happened.
They also describe the procedures vehicle testing stations use to check heavy vehicle handbrakes as "cursory" but hard to improve.
The struggle over what to do about two types of handbrakes, that have each been implicated in several truck runaway deaths, is detailed in emails and reports released by WorkSafe under the OIA.
Two people died when Sanwa Seiki brakes failed in 2010 and 2019; three people have been crushed by two runaway trucks and a telehandler with cardan shaft handbrakes - sometimes called transmission handbrakes - in 2017, 2018 and 2020.
The documents reveal this sparked investigations in each of the last three years by the Transport Agency.
The first two inquiries involved just a few trucks each: In one, one of the six trucks ran away with a full load on; in the other, none did, but the investigators concluded that cardan shaft brakes sometimes needed such force to pull on, it would take two hands.
The third inquiry, last year following a fatality in March, was much bigger - and more worrying, finding high rates of failure.
Notes from WorkSafe say NZTA negotiated with UD Trucks - which had taken over from Nissan - in 2019 to get new Sanwa Seiki brake levers into "all affected trucks... by July 2020 (approx 1200 units)."
That is now not happening till September this year. RNZ has asked Waka Kotahi if this was delayed by the pandemic.
However, John Gerbich of UD Trucks recalled the 2019 meeting differently. He said they agreed with the agency the best approach was to require trucks to get a brake check by a mechanic before going for a Certificate Of Fitness (COF).
'Significant delays'
The Sanwa Seiki problem is in hand, but cardan shaft brakes are far more common - in more than 50,000 Japanese-made heavy vehicles and trucks up to 23 tonnes - and harder to remedy.
The 2019 inquiry said even finding a testing station in the first place could be hard.
It needed to put the test-trucks through a COF check prior to running tests, but encountered "significant delay ... representative of the state of the rest of the country".
"Due to many factors, including time, in-service vehicle inspections are necessarily cursory and tools aren't required.
"It is not practical to test every vehicle in unladen and laden conditions."
The problem that remains, as WorkSafe told the Transport Ministry in October 2019, is that "it is clearly possible to pass a COF legitimately while not having a vehicle that is safe in all practical situations of normal operation".
Stretched brake cables are a risk, and the agencies talked about introducing handheld gauges to detect any slack by checking how much force it takes to pull on the handbrake.
Waka Kotahi is still working on getting warning stickers put in truck cabs to remind drivers of handbrake limitations, such as that they can fail with a full load on a hill.
As for using chocks under wheels, the agency told WorkSafe in February this year that "may also send the wrong msg [sic] i.e. 'don't worry about how good the park brake is, just throw some chocks under it, she'll be right'".
RNZ
